This application is co-pending with my eight other patent applications related to a turbine-gear train system describing and claiming various aspects thereof.
This invention relates to a gear train system and more particularly to a means of changing the effective tooth positional accuracy between a gear and a pinion on the same shaft when used with other like units in a parallel or a branched gear system of more than one stage.
When power is transmitted between two stages of any parallel or branched gear system; including an epicyclic, a star or a parallel arrangement of more than one stage; any misalignment between the teeth of the first stage gear and the second stage pinion when assembled in the gear train, causes unbalance loading of the gear teeth. The magnitude of the unbalanced load will be a function of the stiffness of the shaft between the gears, the stiffness of the teeth and the extent of the misalignment. In the past, the first-to-second stage clusters have generally been made as a single member and stringent machining accuracy has been used to result in reasonable positional accuracy. This can be done when the stresses permit machining processes which do not include hardening and grinding and are therefore limited to low-load applications. However, when such systems require limited life, lightweight and high loads, the need for very high wear and bending strength and for optimum load distribution makes use of hardened and ground gears mandatory and forces the cluster to be made of two pieces which are then joined. However, this joining of two pieces amplifies the positional inaccuracy unless tolerated by some other means. It is thus desirable to correct for the positional inaccuracy caused by joining of two pieces in such a gear system used for high loads.